JPS5812911A - Multitubular type once-through boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a multi-tubular once-through boiler.

Conventionally, the water pipes used in multi-tubular once-through boilers are of the bare tube type, which has a disadvantage of having a small heat transfer area per unit volume and requiring a large installation space.

Therefore, it is possible to use a heathered pipe with fins, but the disadvantage is that the flow rate of the combustion gas is slow and a high heat transfer coefficient cannot be achieved with Ikkyu-in water pipes in which the fins are attached circumferentially or in a spiral shape. there were.

In view of the above points, it is an object of the present invention to provide a multi-tubular once-through boiler that requires a small installation space and has good heat transfer.

Hereinafter, an embodiment of the invention of item i will be described based on the drawings. Both the upper header 1 and the lower header 2 are formed in an annular shape. The upper and lower headers 1, 2 are connected by a large number of inner water pipes 3 and outer water pipes 4, and these inner water pipes 3 are arranged as an annular water pipe wall with a slight pitch.

The outer water pipe 4 is also arranged as an annular water pipe wall with a slight gap. It is desirable that the pitch angles of the inner water pipes 3 and the outer water pipes 4 be the same, and the inner and outer water pipes are arranged with a half-pitch shift. A boiler outer wall 5 is provided on the outside of the wood pipe wall at a distance. A combustion chamber 6 is formed within the water tube wall of the inner water tube 3. A combustion device 7 is provided inside the upper header 1. If desired, this combustion device 7 can also be placed in the space formed inside the lower header 2. A wire 8 is attached to the outer water pipe 4 in a circumferential direction or in a spiral shape. It is desirable that the fins 8 be bent at their mutually abutting portions to increase the flow rate of the combustion gas. The folded part has a notch of 9.
This makes bending easier.

Heat transfer promoting plates 10 having a substantially V-shaped cross section are attached to the valleys of the portions of the finned outer water pipes 4 facing the boiler outer wall 5 side, and these heat transfer promoting plates 10 are arranged between the finned outer water pipes 4 and the finned outer water pipes 4. They are arranged in such a way that there is a slight gap between them.

To explain its function in the above configuration, the combustion gas generated in the combustion chamber 6 first exchanges heat with the inner water pipe 3 by radiation heat transfer, flows almost perpendicularly to the water pipe, and is absorbed by the water pipe group. It passes through the formed image while exchanging heat by convection heat transfer, and further passes through the gap formed between it and the heat transfer promotion plate 10 while exchanging heat, and is provided on a part of the boiler outer wall 5. It is discharged to the outside through a chimney (not shown).

As explained above, this invention uses a finned water pipe,
Furthermore, since the heat transfer promoting plate is attached, it is possible to provide a multi-tubular once-through boiler that requires a small installation space and has good heat transfer.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view, and FIG. 3 is a cross-sectional view showing a method of bending the fins. 2 is the lower pipe header, 3-piece inner water pipe, 4
is an outer water pipe, 5 is an outer wall of the boiler, 6 is a combustion chamber, 7 is a combustion device, 8 is a fin, 9 is a notch, 10 is a heat transfer promotion plate 0
1 (Patent applicant Tamotsu Miura Representative Miura Kogyo Co., Ltd. Figure 2 Figure 3

Claims (1)

[Claims] Both the upper header 1 and the lower header 2 are formed in an annular shape, and the upper and lower headers 1 and 2 are connected by a large number of inner water pipes 3 and outer water pipes 4, and these inner water pipes 3 are formed into an annular shape with a slight gap. The outer water pipe 4 is also arranged as an annular water pipe wall with a slight gap, and the fins 8 are attached to the outer water pipe 4 in the circumferential direction or in a spiral shape. Heat transfer accelerator plates 10 having a substantially V-shaped cross section are installed in the valleys of the portion facing the boiler outer wall 5 side, and these heat transfer accelerator plates 10 are designed to have a slight gap between them and the finned outer water pipes 4. A multi-tubular once-through boiler characterized by being installed in a.